Edexcel D1 2002 June — Question 3

Exam BoardEdexcel
ModuleD1 (Decision Mathematics 1)
Year2002
SessionJune
TopicCombinations & Selection

3. \begin{figure}[h]
\captionsetup{labelformat=empty} \caption{Figure 1} \includegraphics[alt={},max width=\textwidth]{652477eb-87dc-4a5a-8514-c9be39986142-3_444_483_401_489}
\end{figure} \begin{figure}[h]
\captionsetup{labelformat=empty} \caption{Figure 2} \includegraphics[alt={},max width=\textwidth]{652477eb-87dc-4a5a-8514-c9be39986142-3_444_478_401_1106}
\end{figure} Five members of staff \(1,2,3,4\) and 5 are to be matched to five jobs \(A , B , C , D\) and \(E\). A bipartite graph showing the possible matchings is given in Fig. 1 and an initial matching \(M\) is given in Fig. 2. There are several distinct alternating paths that can be generated from \(M\). Two such paths are $$2 - B = 4 - E$$ and $$2 - A = 3 - D = 5 - E$$
  1. Use each of these two alternating paths, in turn, to write down the complete matchings they generate. Using the maximum matching algorithm and the initial matching \(M\),
  2. find two further distinct alternating paths, making your reasoning clear. \begin{figure}[h]
    \captionsetup{labelformat=empty} \caption{Figure 3} \includegraphics[alt={},max width=\textwidth]{652477eb-87dc-4a5a-8514-c9be39986142-4_577_1476_367_333}
    \end{figure} Figure 3 shows the network of paths in a country park. The number on each path gives its length in km . The vertices \(A\) and \(I\) represent the two gates in the park and the vertices \(B , C , D , E , F , G\) and \(H\) represent places of interest.